1. Field of the Invention
The invention relates to attachments for construction equipment. In particular, the invention is an arm extension that is easily installed on the shovel of a backhoe to extend the reach and functionality of the skiploader arm.
2. Description of the Related Art
In the construction industry, labor and capital equipment costs are the primary variables that affect the cost of a particular project. Of course, in order to remain competitive, a construction contractor must minimize the cost of a project while meeting predetermined specifications. To this end, large machinery has been used to more efficiently handle tasks that were originally accomplished by hand, such as digging, lifting, and moving objects. For example, bulldozers (or graders) have been used to push large amounts of earth for grading and other tasks.
A bulldozer is typically a tractor-like machine having a blade mounted on a frame that extends forward of the tractor body of the bulldozer. The blade is used to push dirt or other objects that need to be moved. The blade can be moved up and down slightly relative to the body to compensate for slopes and other irregularities in the ground. However, a bulldozer is limited to pushing dirt or the like along the ground. In order to lift and move large amounts of dirt or the like, other machinery is necessary. Of course, construction machinery is expensive and is often rented by the hour or by the day. Therefore, limiting the amount of machinery used on a particular project; and making constant use of the available machinery is desirable to limit costs.
In view of this, a device known as a "backhoe" has been developed. A backhoe is a very versatile piece of machinery and thus has become the most widely used piece of construction machinery. A backhoe is capable of doing much of the work of a bulldozer and more. A typical backhoe includes a basic 4-wheel tractor, a front end leader having a pair of extending primary arms mounted to the tractor, a pair of extending secondary arms connected to free ends of the primary arms, and an upwardly directed bucket pivotally mounted on free ends of the secondary arms. Hydraulic cylinders, or the like, are mounted on the various arms and controlled to cause the bucket to be positioned in various desired positions. The bucket can be used to scoop and lift large amounts of dirt or the like.
Additionally a backhoe has a hydraulically controlled digger, known itself as a "backhoe" or a "backhoe digger ", disposed on the tractor at an end opposite to the bucket. Note that the term "backhoe" as used herein refers any construction machine including a tractor and backhoe digger. The backhoe digger loader includes a primary arm pivotally attached to the tractor, a secondary arm pivotally attached to the primary arm, and a downwardly directed shovel disposed on the free end of the secondary arm. The backhoe digger shovel is generally smaller than the front end loader bucket and the arms of the backhoe digger are relatively long to facilitate digging deep holes or reaching high to scoop or dump dirt or the like.
This construction provides a backhoe with the versatility to accomplish a broad range of construction tasks. However, a backhoe does have some limitations. In particular, a conventional backhoe cannot easily lift large relatively fragile objects, such as a stack of plywood or the like. Also, a conventional backhoe has a limited extension and cannot take advantage of the extension of the backhoe digger arms for lifting large objects because of the relatively small size of the backhoe digger shovel. Further, even the extension of the backhoe digger arms, if it could be used for lifting, is often inadequate for picking up and placing large objects.
It is well known to provide attachments to construction machinery. For example, U.S. Pat. No. 4,200,423 issued to Somsin, U.S. Pat. No. 3,812,979 issued to Leihgeber, and U.S. Pat. No. 3,587,887 issued to DeCarli each disclose a boom attachment for front bucket loaders in which a boom is attached to an upwardly directed front bucket. The attachments disclosed by Somsin, Leihgeber, and DeCarli couple to the open face of a front bucket and require a complex rigid attachment to the bucket through bolts or the like. None of Somsin, Leihgeber or DeCarli relate to a backhoe having a backhoe digger and thus the attachments disclosed in these patents are not suitable for mounting on a downwardly directed backhoe digger shovel.
It is also known to provide attachments for a backhoe digger arm. For example, U.S. Pat. No. 4,523,684 issued to Baisden discloses a crane attachment for a backhoe. However, this device requires removal of the skiploader bucket and complex coupling between the hydraulic control system of the backhoe and the crane attachment.
In summary, attempts have been made to increase the versatility of backhoes by providing backhoe digger arm attachments. However, prior inventors have found it necessary to use complex connections which interfere with normal use of the backhoe. Therefore, the prior art attachments introduce limitations.